What’s the Difference between Blackwater and Greywater?
Without water, life would be impossible. It is very important for the survival of man and all living beings.
We drink it to quench our thirst, use it to grow our food, cleanse our bodies and utensils, and for recreation and exercise.
According to WHO, nearly a billion people lack access to clean drinking water and an estimated 500 million die each year from disease associated with contaminated sources.
Climate change is another driver that affects fresh water availability. In this case shifting climate modifies precipitation patterns leading to extreme drought in areas as can be seen in the NOAA’ s current projections.
Fresh water stress can be addressed to a degree with advanced water treatment technology. Wastewater produced domestically can be classified into two categories: blackwater and greywater. Although they are both wastewater, the levels of contamination are different, which is why they must be treated differently.
(Both varieties can be recycled through treatment systems and are often reused for irrigation and cleaning)
So what are the differences between blackwater and greywater?
Blackwater: is the wastewater from bathrooms and toilets that contains faecal matter and urine. Water from kitchens and dishwashers are also considered blackwater due to the contamination by pathogens and grease. It is also referred to as sewage or brown water and can carry disease and bacteria, both of which could be harmful. The most common way to treat blackwater has been biological or chemical treatment and the use of disinfectants has been required for treating blackwater.
The most common wastewater treatment and reuse system has up to now been the aerated system – which usually involves going from “big to small” where wastewater solids are firstly removed, the the effluent is aerated to assist bacterial breakdown of organic matter, and finally a disinfection.
As of todays situation with different types of pollution, more advanced water treatment technologies are called for, requirements will be made to process the water to the point that it can be reused in a meaningful way.
Additionally, there is growing concern regarding micro-pollutants, such as Pharmaceuticals and personal care products, which have been detected in drinking water, unfortunately not removed by conventional methods. New regulatory action, regarding the removal of these contaminants by water treatment plants will also require advanced technology. New and emerging technology that potentially address the removal of micro- pollutants in both drinking drinking water as well as to wastewater is and will be plasma based water purification filter systems. Clearwell markets a system combination consisting of an initial pre-filtering, polypropylen filtration, nano/micro-fibers specially developed sorbents to remove heavy metals as well as some toxic organic compounds, Plasma treated stainless steel nets and a Hydrophilic filter filter construction consisting of asymmetric Polyethersulfone membranes and Polypropylene hardware that will treat black waste water efficiently.
Greywater: is the wastewater that comes from sinks, washing machines, bathtubs and showers. It contains lower levels of contamination, making it easier to treat and process.
Recycled greywater is commonly used in irrigation and constructed wetlands – as long as no harmful chemicals are present. Greywater that contains food particles can nourish plants, it can also be used for washing and flushing toilets. Where water is scarce - greywater is valuable.
Greywater can be reused in gardens with little or no treatment through a subsurface irrigation system to evenly spread water around in the garden. This method is safer for untreated greywater; however all treatment recommendations depend on the condition of the greywater. The quality of reused water will depend on the treatment system, the water’s previous use and chemicals used at the source.
Domestically you can take measures at the “source”, like minimise the use of harsh chemical cleanings, use low or no sodium laundry detergents, soaps and shampoos, do not dispose of household chemicals down sink – your local council will have chemical collection services available and use a sink strainer in the kitchen to prevent food scraps and other solid material entering the wastewater facilities.
Clearwell Europe AB supplies a mobile multi level water purification system, customised for any degree of pollution, be it blackwater or greywater from a small community, a recycling facility in Denmark, a mine in Sweden or system for rural water purification in the amazon. We have a solution for your unique need!
